There is a need for a sensing system to monitor manually applied forces and torques. An example of such a sensor system is described in U.S. Pat. No. 3,921,445 to Hill and Sword. In that specification, the manipulator is of a hand-like form comprising a pair of jaws, which are relatively pivotally movable under operation of an electric motor. The manipulator includes a wrist. Sensing means are provided for sensing the magnitude and direction of applied forces and torques. The applied force is decomposed into components corresponding to three mutually orthogonal axes intersecting at the wrist. The sensing means include a series of sensors extending around the longitudinal axis of the manipulator.
U.S. Pat. No. 4,811,608 to Hilton, entitled FORCE AND TORQUE CONVERTER, issued Mar. 14, 1989, utilizes an architecture in which six connection members extend radially from a central mounting block to a grip. Each connection member extends along one of three mutually orthogonal axes. Sensing mechanisms are disposed to detect the displacement of the connection members and thereby determine the applied force and/or torque.
U.S. Pat. No. 4,550,617 to Fraignier et al., entitled MULTI AXIS FORCE AND MOMENTS TRANSDUCER, issued Nov. 5, 1985, utilizes an architecture in which two bodies are connected by a plurality of flexible plates, subdivided into pairs. Each pair is arranged to have one plate being orthogonal to the other. Strain gauges detect the flexing of each plate.
The prior art force and torque converters are expensive and for a wide variety of applications actually are prohibitively expensive. Thus, a lower cost but still highly reliable torque and force converter is needed in the marketplace.